3 . It is stupid to do that. It is quite unnecessary.

It is quite unnecessary and stupid to do that

4 . I wanted to go. He wanted to stay.

I wanted to go but he wanted to stay.

5 . Your arguments are strong. They don’t convince me.

Your arguments are strong but they don’t convince me.

6 .  You can go there by bus. You can go there by train.

You can go there either by bus or by train.

7 . I was feeling tired. I went to bed when I got home.

I was feeling tired so I went to bed when I got home.